Japanese Patent Publication No. 3387487 discloses an image display device which displays an image on a large screen and thereby can give a realistic image to an observer. The image display device can give an immersion feeling to the observer by providing an image capable of covering the observer's view. Such an image display device, which can not only simply display an image to an observer but also give more natural vision, such as wide field of view, stereoscopic vision, or full-size vision, is required in many fields.
By the way, in such an above image display device, there was a request that a user wants to adjust the height of the screen according to the user's height or uses thereof. However, in the above image display device, because the position of the screen is fixed, it was not possible to adjust the height of the screen according to the user's height or the uses thereof.